Identities & Reciprocals

What is an identity?

An identity is when two terms are "the same as" each other, over the normal equals meaning "is equal to". For example
\(x=6\) is not an identity, but \(2x=x+x\) is. An identity is represented by an equals-sign-like symbol with three
horizontal lines: \(\equiv\). You can write them with a regular \(=\), as this is obviously still true.